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wadesc
New User
Mar 14, 2010, 8:22 AM
Post #1 of 2
(3650 views)
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2000 toyota tacoma
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I have a 2000 toyota tacoma, the fuel pump wont work. I have replaced the fuel pump, swapped out relays and checked all fuses in regards to the fuel pump. I have power to one of the leads ot the relay but no power at the wiring plug at the fuel pump. It's possible I've missed something but I've checked things more than once. Any help or advice wpuld be greatly appreciated. The truck is a 4 cylinder if that makes a difference.
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DanD
Veteran
/ Moderator
Mar 15, 2010, 8:09 AM
Post #2 of 2
(3635 views)
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Re: 2000 toyota tacoma
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When the ignition is first turned on the EFI relay (under hood relay box #2) should close (turn on). The EFI relay’s pull-in coil is protected by a 7.5 amp fuse in junction box #1 (under dash left of steering column); it should have power with the ignition in the on or run position.
The EFI relay receives its switched power from a 15amp fuse in relay box #2; it should have power at all times.
Once the EFI relay is closed (switched on); power is fed to the pull-in coil and the switched circuit of the “circuit opening relay” (fuel pump relay). You’ll find it behind the dash above the steering column. Once the computer sees an rpm signal, it grounds the pull-in coil circuit; which in turn closes the relay and turns the fuel pump on.
Just to add a little more confusion to the fuel pump wiring; the “circuit opening relay” has a second pull-in coil; that closes the relay; to turn the pump on during cranking. It does this to begin building fuel pressure during cranking; so that when the computer sees rpm the fuel system is up and running. In other words if the engine is not being cranked by the starter motor or the computer doesn’t see an rpm signal; the fuel pump will not be turned on.
My reasoning for writing this out is to show that there’s more then one relay and fuse; there’s also a number of splices (connection points), switches and the computer; that are involved in getting the fuel pump up and running.
Having a good working knowledge of how the system should work is just the beginning of finding the root cause of this problem.
Even here at the shop with our manuals, wiring diagrams and test equipment; we find ourselves chasing our tails, looking for a problem at times.
Maybe the above will help; if not take it in to someone that can do this for you. No sense to keep throwing parts at this vehicle or beating your head against the wall looking for the fault.
Dan.
Canadian "EH"
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